A polyacetal resin, which is excellent in mechanical properties, thermal properties, electrical properties, slidability, moldability and the like, is widely used mainly in electrical devices, automotive parts, precision machinery components and the like as a structural material and a mechanism component. As a polyacetal resin is used in increasingly broader fields, required properties tend to become more advanced, complicated and specialized.
For example, in the field of automotive parts, excellent fuel-resistance may be required. A polyacetal resin has excellent fuel-resistance among other thermoplastic resins, and used in large components such as those directly contacting with a fuel oil, for example, a fuel supply unit and the like represented by a fuel pump module.
Moreover, a method of further improving the fuel-resistance of a resin molded body manufactured with a polyacetal resin has been explored. For example, Patent Document 1 discloses a polyacetal resin composition having excellent fuel-resistance even in severe environments.
Patent Document 1: Japanese Unexamined Patent Application